I looked around, but couldn't find an answer to this question: what sets Purify apart from other issue trackers?
* If I know how to use Trac/Redmine, why use Purify?
* Why choose it over other hosted trackers, specifically Lighthouse?
* If I have Github Issues built-in to Github, why would I choose Purify?
Edit: I'm not saying there's no compelling reason to use Purify, I'd just like to hear the team's take.